This disclosure relates to fuse holders of the type made for holding cylindrical replaceable fuses with a diameter of 1/4 inch and a tubular length of 11/4 inches. These fuses have metal cup shaped end caps with their open ends facing and connected therebetween by a fusible link. A hollow tube of glass or other insulating material is disposed to separate and support the metal cup shaped ends in alignment with each other and to protect the fusible link which passes therethrough. The fuse holders for such fuses generally include terminals which engage the cup shaped fuse ends thereby to electrically connect the fusible link in series with the circuit to be protected. The connection terminals are normally configured to resiliently engage the metal cup shaped ends and hold them for electrical connection and ease of fuse replacement. Such fuse holders are often located such that the insulating glass tube allows visual examination of the connection of the fusible link whereby electrical continuity of the fuse can be determined.
Generally, the fuse holder also has an insulative support base to position the resilient terminals apart and in-line with one another to receive the fuse end caps of a cylindrical fuse and to support the glass insulating tube between the terminals. Such fuse support bases can be a molded polymeric insulating material having a high dielectric and the molded base can include mounting provisions for attaching the terminals to the base. Moreover, the support base can be arranged to carry a plurality of terminals to locate a number of fuses side by side in parallel spaced relation to one another. The fuse support base could also include an area for severance so that a plurality of parallel fuse holders can be split apart to form individual fuse holders or any selected number of fuse holders on a common support base. Consequently, a preferred number of fuse holders can be obtained from a strip containing a large number of holders by cutting the base at selected areas. Prior art arrangements are often wasteful of material and difficult to use, and may also be difficult to manufacture and assemble.
The fuse holders of the type described may suffer from problems associated with the fact that the cylindrical fuses described are generally for relatively low voltage circuits used in severe environments, such as equipment subject to vibration. Therefore, an excellent contact terminal design is required to facilitate good physical and electrical connection between fuse and terminal. The resilient terminals normally used are spring type of electrically conducting metal material configured to receive and hold the cup shaped metal cap ends, while maintaining electrical contact. The most common terminal configuration is U-shaped to circumscribe a part of the circular end cap of the fuse and is specifically arranged to conjugate with the circular cross sectional shape of the end cap, except at its open side, i.e., the mouth of the U-shaped terminal. In addition, the terminals have connection lugs to receive solder or solderless terminals, or threaded fasteners or the like to ease its electrical connection with a circuit.
There are terminals designed to cooperate during assembly with the specially configured portions of an insulative support base, but the generally inflexible support base material hampers effective and secure assembly. None of the prior designs manage completely to securely position the terminal on the fuse support base and resist movement and defy fatigue associated with use in a vibration prone environment. Little has been done to assure both good terminal contact and ease of terminal positioning on the support base. In particular, the forces applied during insertion and removal of the fuse from the terminals or applied during connection to the circuit with solderless terminals, threaded fasteners or the like must be resisted by the terminal mounting to its support base and the base attachment to its support chassis. In particular, the design of the support base must be such as to accurately secure the terminal and thereby assist in the operation of receiving and holding the fuse in position. Notwithstanding the foregoing requirements, fuse replacement must be easily performed.
In order to overcome the deficiencies of the available fuse holders and provide an improved arrangement with advantages and features heretofore unknown and unappreciated, it is an object of this disclosure to set forth an improved and easy to use fuse holder.
It is another object of the invention disclosed to teach a low cost fuse holder capable of reliable operation and securely supporting fuses for excellent electrical connection in a circuit.
It is a further object of the invention disclosed to have a design for a terminal clip which is securely mounted to its base by an easy low cost manner of assembly whereby the terminal mounting will resist movement between base and clip.
It is yet a further object of the invention illustrated herein to show an easily severable support base design which allows the common fuse support base for a plurality of fuses to be readily and cleanly separated into individual fuse holders or fuse holder sets.